The SP stopped running presidential candidates after 1956, when its nominee Darlington Hoopes won fewer than 6,000 votes. In the party's last decades, its members, many of them prominent in the labor, peace, civil rights and civil liberties movements, fundamentally disagreed about the socialist movement's relationship to the labor movement and Democratic Party in the U.S., and about how best to advance democracy abroad. In 1970–1973, these strategic differences had become so acute that the Socialist Party changed its name to Social Democrats, USA. Leaders of two of its caucuses formed separate socialist organizations, the Democratic Socialist Organizing Committee and the Socialist Party USA.

"The few own the many because they possess the means of livelihood of all.... The country is governed for the richest, for the corporations, the bankers, the land speculators, and for the exploiters of labor. The majority of mankind are working people. So long as their fair demands - the ownership and control of their livelihoods - are set at naught, we can have neither men's rights nor women's rights. The majority of mankind is ground down by industrial oppression in order that the small remnant may live in ease."

From 1901 to the onset of World War I, the Socialist Party had numerous elected officials. There were two Socialist members of Congress, Meyer London of New York City and Victor Berger of Milwaukee (a part of the sewer socialism movement, a major front in socialism, Milwaukee being the first city (and the only major one) to elect a socialist mayor, which it did four times between 1910 and 1956); over 70 mayors, and many state legislators and city councilors. Its voting strength was greatest among recent Jewish, Finnish and German immigrants, coal miners, and former Populist farmers in the Midwest.[4] From 1900 (before its formal union) to 1910, the Socialist Party ran Eugene Debs for President at each election. The best showing ever for a Socialist ticket was in 1912, when Debs gained 901,551 total votes, or 6% of the popular vote. In 1920 Debs ran again, this time from prison, and received 913,693 votes, 3.4% of the total.

Early political perspectives ranged from radical socialism to social democracy, with New York party leader Morris Hillquit and Congressman Berger on the more social democratic or right wing of the party and radical socialists and syndicalists, including members of the Industrial Workers of the World (IWW) and the party's frequent candidate, Eugene V. Debs, on the left wing of the party. As well there were agrarian utopian-leaning radicals, such as Julius Wayland of Kansas, who edited the party's leading national newspaper, Appeal to Reason along with trade unionists; Jewish, Finnish, and German immigrants; and intellectuals such as Walter Lippmann and the Black activist/intellectual Hubert Harrison.

The party had a tense and complicated relationship with the American Federation of Labor. The American Federation of Labor leadership, headed by Samuel Gompers, was strongly opposed to the SPA, but many rank and file unionists in the early party of the 20th Century saw in the Socialists reliable political allies. Many moderate Socialists, such as Victor Berger and International Typographical Union President Max S. Hayes, urged close cooperation with the American Federation of Labor and its member unions. Others in the Socialist Party's ranks dismissed the American Federation of Labor and its craft unions as antiquated and irrelevant, instead favoring the much more radical IWW and the syndicalist path to socialism.

In 1911, IWW leader William "Big Bill" Haywood was elected to the National Executive Committee of the Socialist Party, on which American Federation of Labor partisan Morris Hillquit also served. The syndicalist and the electoral socialist squared off in a lively public debate in New York City's Cooper Union on Jan. 11, 1912, with Haywood declaring that Hillquit and the socialists ought to try "a little sabotage in the right place at the proper time" and attacked Hillquit for having abandoned the class struggle by helping the New York garment workers negotiate an industrial agreement with their employers. Hillquit replied that he had no new message rather than to reiterate a belief in a two-sided workers movement, with separate and equal political and trade union arms. "A mere change of structural forms would not revolutionize the American labor movement as claimed by our extreme industrialists," he declared.[5]

The issue of "syndicalism vs. socialism" was bitterly fought over the next two years, consummated by "Big Bill" Haywood's recall from the SPA's NEC and the departure of a broad section of the left wing from the organization. The memory of this split made the intra-party battles of 1919-1921 all the more bitter.

Eugene V. Debs, founding member and icon of the SPA.

The party's opposition to World War I caused a sharp decline in membership. An increase in the membership of its language federations from areas involved in the Bolshevik Revolution proved illusory, since these members were soon lost to the Communist Party.

The Left Wing Section of the Socialist Party emerged as an organized faction early that same year, building its organization around a lengthy Left Wing Manifesto authored by Louis C. Fraina. This effort to organize in order to "win the Socialist Party for the Left Wing" met with staunch resistance from the "Regulars" who controlled a big majority of the seats of the SPA's governing National Executive Committee. When it seemed certain that the 1919 party elections for a new NEC had been dominated by the Left Wing, the sitting NEC, citing voting irregularities, refused to tally the votes, declared the entire election invalid and in May 1919 suspended the party's Russian, Latvian, Ukrainian, Polish, South Slavic, and Hungarian language federations, in addition to the entire state organization of Michigan. In future weeks, the state organizations of Massachusetts and Ohio would similarly be disfranchised and "reorganized" by the NEC, while in New York and Pennsylvania, the "Regular" State Executive Committees undertook reorganization of Left Wing branches and locals on a case-by-case basis.

Executive Secretary Adolph Germer was one of 5 top SPA leaders prosecuted by the Department of Justice in 1919.

In June 1919, the Left Wing Section held a conference in New York City to discuss their organizational plans. The group found themselves deeply divided, with one section, led by NEC members Alfred Wagenknecht and L. E. Katterfeld and including famed radical journalist John Reed favoring a continued effort to gain control of the SPA at its forthcoming Emergency National Convention in Chicago, to be held at the end of August, while another section, headed by the Russian Socialist Federation of Alexander Stoklitsky and Nicholas Hourwich and the Socialist Party of Michigan seeking to wash their hands of the Socialist Party and immediately move to the establishment of a new Communist Party of America. Eventually this latter Federation-dominated group was joined by important Left Wingers C. E. Ruthenberg and Louis Fraina, a depletion of Left Wing forces which made the result of the 1919 Socialist Convention a foregone conclusion.

Alfred Wagenknecht, top leader of the 1919 SPA Left Wing.

Regardless, the plans of Wagenknecht, Reed & Co. to fight it out at the 1919 Emergency National Convention continued apace. With the most radical state organizations effectively purged by the Regulars (Massachusetts, Minnesota) or unable to participate (Ohio, Michigan), and the Left Wing language federations suspended, a big majority of the hastily elected delegates to the gathering were controlled by the Executive Secretary Adolph Germer and the Regulars. A group of Left Wingers without delegate credentials, including John Reed and his sidekick Benjamin Gitlow, made an effort to occupy chairs on the convention floor before the gathering was called into order. The incumbents were unable to block the Left Wingers at the door, but soon called the already present police to their aid, and the officers of the law obligingly expelled the boisterous radicals from the hall. With the Credentials Committee firmly in the hands of the Regulars from the outset, the outcome of the gathering was no longer in doubt and most of the remaining Left Wing delegates departed, to meet with other co-thinkers downstairs in a previously reserved room in a parallel convention. It was this gathering which established itself as the Communist Labor Party on August 31, 1919.

Meanwhile, elsewhere in Chicago the Federations and Michiganders and their supporters established the Communist Party of America at a convention gaveled to order on September 1, 1919. Unity between these two communist organizations was a lengthy and complicated process, formally taking place at a secret convention held at the Overlook Mountain House hotel near Woodstock, New York in May 1921 with the establishment of a new unified "Communist Party of America."

A Left Wing loyal to the Communist International remained in the Socialist Party through 1921, continuing the fight to bring the SPA into the ranks of the Comintern. This group, which opposed the underground secret organizations which the Communist Parties had become, included noted party journalist J. Louis Engdahl and William Kruse, head of the party's youth affiliate, the Young People's Socialist League, as well as a significant segment of the SPA's Chicago organization. These left wing dissidents continued to make themselves heard until their departure from the party after the convention of 1921.

The five Socialist Assemblymen suspended by the New York State Legislature in January 1920.

Sweet attacked the five, declaring they had been "elected on a platform that is absolutely inimical to the best interests of the state of New York and the United States." The Socialist Party, Sweet said, was "not truly a political party", but was rather "a membership organization admitting within its ranks aliens, enemy aliens, and minors." The party had denounced America's participation in the European war and had lent aid and comfort to Ludwig Martens, the "self-styled Soviet Ambassador and alien, who entered this country as a German in 1916." It had supported the revolutionaries in Germany, Austria, and Hungary, Sweet continued, and consorted with international Socialist parties close to the Communist International.[8] Sweet concluded:[9]

It is every citizen's right to his day in court. If this house should adopt a resolution declaring your seat herein vacant, pending a hearing before a tribunal of this house, you will be given an opportunity to appear before such tribunal to prove your right to a seat in this legislative body, and upon the result of such hearing and the findings of the Assembly tribunal, your right to participate in the actions of this body will be determined.

The Assembly suspended the quintet by a vote of 140 to 6, with one Democrat supporting the Socialists. Civil libertarians and concerned citizens raised their voices to aid the suspended Socialists, and protest percolated throughout the press. The principal argument was that majority parties expelling elected members of minority parties from their councils set a dangerous precedent in a democracy.[10] The battle culminated in a highly publicized trial in the Assembly, which dominated the body's activity from its opening on January 20, 1920, until its conclusion on March 11. Socialist Party leader and former 1917 New York City mayoral candidate Morris Hillquit served as chief counsel for the suspended Socialists, aided by party founder, and future Socialist Vice Presidential candidate, Seymour Stedman.

At the trial, Hillquit charged that Speaker Sweet had made a "specific, concrete, definite, affirmative declaration of guilt" of the five Assemblymen before they were ever charged with any offense. It was the chief accuser, Speaker Sweet, who also appointed the members of the Judiciary Committee to which the matter was referred. "Thus the accuser selects his own judges," Hillquit declared.[11] Hillquit sought to remove for reasons of bias any members of the Judiciary Committee who had taken part in the activities of the Lusk Committee, the New York State Senate's anti-radicalism committee. Hillquit particularly challenged the presence of Assemblyman Louis A. Cuvillier, who had stated on the floor of the house the previous night words to the effect that "if the five accused Assemblymen are found guilty, they ought not to be expelled, but taken out and shot."[12] The Assembly voted overwhelmingly for expulsion on April 1, 1920.

A special election was held September 16, 1920, to fill the five seats vacated by the Assembly, with each of the five expelled Socialists running for re-election against a "fusion" candidate representing the combined Republican and Democratic parties. All five Socialists were returned to office.[13]

Three of the five, Waldman, Claessens, and Solomon, were again denied their seats after a contentious debate by votes of 90 to 45 on September 21, 1920. Orr and DeWitt, deemed less culpable than their peers by the earlier findings of the Judiciary Committee, were seated by votes of 87 to 48. In solidarity with their ousted colleagues, the pair refused to take their seats.[14]

After the five seats were again vacated, Morris Hillquit expressed his disappointment at the "unconstitutional action" of the Assembly. However, Hillquit continued, "it will draw the issues clearer between the united Republican and Democratic parties representing arbitrary lawlessness, and the Socialist Party, which stood and stands for democratic and representative government."[14]

The legislature attempted to prevent the election and seating of Socialists in the future by passing laws designed to exclude the Socialist Party from recognition as a political party and to alter the legislature's oath-taking procedures so that elected members could be excluded before being sworn. Governor Al Smith vetoed the legislation.[15]

Morris Hillquit, Chairman of the SPA from the death of Debs until he himself died in 1933.

In the first half of 1919, the Socialist Party had over 100,000 dues paying members; by the second half of 1921, it had been shattered. Fewer than 14,000 members remained in party ranks, with the departure of the large and well-funded Finnish Socialist Federation adding to the malaise.[16] In September 1921, the NEC of the party determined that the time had come to end the party's historic aversion to "fusion" with other political organizations and issue an appeal declaring that the "forces of every progressive, liberal, and radical organization of the workers must be mobilized" to repel conservative assaults and "advance the industrial and political power of the working class."

This desire for common action seems to have been shared by various unions, as late in 1921 a call was issued in the name of the country's 16 major railway labor unions seeking a "Conference for Progressive Political Action" (CPPA). The CPPA was originally intended to be an umbrella organization bringing together various elements of the farmer and labor movement around a common program. Invitations to the group's founding conference were issued to members of a wide variety of "progressive" organizations of widely varied perspectives. As a result, from its inception the heterogeneous body was unable to agree on even a program or even a declaration of principles, let alone congeal into a new political party.

The Socialist Party was an enthusiastic supporter of the CPPA, and the group dominated its thinking from the start of 1922 through the first quarter of 1925. The party sought, in this period of organizational weakness, to forge lasting ties with the existing trade union movement leading in short order to a mass labor party in the United States on the British model.

A first National Conference of the CPPA was held in Chicago in February 1922, attended by 124 delegates representing a broad spectrum of labor, farmer, and political organizations. The gathering passed an "Address to the American People," stating its criticism of existing conditions and formally proposing an amorphous plan of action validating the status quo ante: the labor unions on the group's right wing to endorse labor-friendly candidates of the Democratic Party, the Socialists and Farmer-Labor Party adherents on the group's left wing to conduct their own independent campaigns.[17][18] Perhaps the most important thing the CPPA did at its first National Conference, from the Socialist Party's perspective, was agree to meet again. The SP leadership understood the process of building an independent third party which could count on the allegiance of the country's trade union leadership would be a protracted process, and the mere fact of "agreement to disagree" but nevertheless meeting again was regarded as a step forward.

The communist movement also sought to pursue the strategy of bursting from its isolation through the formation of a mass Farmer-Labor Party. Finally emerged from its underground existence in 1922, the Communists' through their "legal political party," the Workers Party of America decided to send four delegates to the December 1922 gathering of the CPPA.[19] However, the Credentials Committee, after protracted debate, strongly objected to the participation of Communist representatives in its proceedings and issued a recommendation that the representatives of the Workers Party and its youth organization not be seated. The Socialist Party's delegates were strongly in favor of the exclusion of the Communists and acted accordingly, even though the two organizations shared a vision of a party akin to the British Labour Party in which constituent political groups jointly participated while retaining their independent existence. The fissure between the organizations was thus widened.

As with the first conference, the 2nd Conference of the CPPA split over the all-important issue of an independent political party, with a proposal by five delegates of the Farmer-Labor Party calling for "independent political action by the agricultural and industrial workers through a party of their own" defeated by a vote of 52 to 64. A majority report declaring against an independent political party was instead adopted.[20] This defeat of the bid for an independent political party cost the CPPA one its major component organizations, with the Farmer-Labor Party delegation announcing that their group would no longer affiliate with the CPPA after the close of the convention. Although the Socialists did not realize it at the time, the chances that the organization would ever be transformed into an authentic mass Farmer-Labor party of the British Labour type were greatly lessened with the departure of the FLP.

Still, the Socialists remained optimistic. The May 1923 National Convention of the SP voted, after lengthy debate, to retain its affiliation with the CPPA and to continue its work for an independent political party from within that group. The May 20 vote in favor of maintaining affiliation with the CPPA was 38-12.[21] Failing a mass farmer-labor party from the CPPA, the Socialists sought at least a powerful presidential nominee to run in opposition to the old parties. A 3rd National Conference of the CPPA was held in St. Louis, Missouri on February 11 and 12, 1924, a gathering which punted on the issue of committing itself to the 1924 presidential campaign, deciding instead to "immediately issue a call for a convention of workers, farmers, and progressives for the purpose of taking action on nomination of candidates for the offices of President and Vice President of the United States, and on other questions that may come before the convention." [22]

The decisive moment finally came on the 4th of July, 1924, a date which was not accidentally selected. The 1st National Convention of the CPPA was assembled in Cleveland at the city auditorium, which was packed with close to 600 delegates representing international unions, state federations of labor, branches of cooperative societies, state branches and national officers of the Socialist, Farmer-Labor, and Progressive Parties as well as the Committee of 48, state and national affiliates of the Women's Committee on Political Action, and sundry individuals. Very few farmers were in attendance.

The National Committee had previously requested that Wisconsin Senator Robert M. La Follette, Sr. make a run for the presidency. The Cleveland Convention was addressed by the Senator's son, Robert M. LaFollette, Jr., who read a message from his father accepting the call and declaring that the time had come "for a militant political movement independent of the two old party organizations." LaFollette declined to lead a third party, however, seeking to protect those progressives elected nominally as Republicans and Democrats. LaFollette declared that the primary issue of the 1924 campaign was the breaking of the "combined power of the private monopoly system over the political and economic life of the American people." After the November election a new party might well be established, LaFollette stated, around which all progressives could unite.[23]

The Socialist Party enthusiastically supported the independent candidacy of LaFollette, declining to run their own candidate in November 1924. Although the LaFollette candidacy garnered five million votes, it failed to seriously challenge the hegemony of the old parties and was regarded by the unions as a disappointing failure.

Following the election, the governing National Committee of the CPPA met in Washington, DC. While the body had a mandate from the July convention to issue a call for a convention to organize a new political party, the representatives of the critical railway unions, with the exception of William H. Johnston of the Machinists, were united in opposition to idea. The railroad unions instead proposed a motion not to hold the 1925 organizational convention. This proposal was defeated by a vote of 30 to 13. Following their defeat on this question, the railroaders on National Committee members withdrew from the meeting, announcing that they would await further instructions from their respective organizations with regards to future participation.[24] The loss of the very unions who had brought about the CPPA spelled its demise.

A convention to decide on the formation of a new political party was nonetheless scheduled by the National Committee for February 21, 1925, to be held in Chicago. Labor, the official organ of the railway unions, did nothing to promote this 2nd Convention of the CPPA, stating that since the executives of the various unions had taken no stance on the matter, it would be up to subordinate sections to consider sending delegates themselves.[24]

The February 1925 convention found its task was virtually insurmountable, however, as the heterogeneous organization had split over the fundamental question of realignment of the major parties via the primary elections process as opposed to establishment of a new competitive political party. The railway unions, whose efforts who had originally brought the CPPA into existence, were fairly solidly united against the Third Party tactic, instead favoring continuation of the CPPA as a sort of pressure group for progressive change within the structure of the Democratic and Republican parties.

L. E. Sheppard, President of the Order of Railway Conductors of America, presented a resolution calling for a continuation of the CPPA on non-partisan lines as a political pressure group. This proposal was met by an amendment by Morris Hillquit of the Socialist Party, who called the five million votes cast for LaFollette an ecouraging beginning and urged action for establishment of an American Labor Party on the British model — in which constituent groups retained their organizational autonomy within the larger umbrella organization. A third proposal was made by J.A.H. Hopkins of the Committee of Forty-Eight, which called for establishment of a Progressive Party built around individual enrollments. No vote was ever taken by the convention on any of the three proposals mooted. Instead, after some debate the convention was unanimously adjourned sine die — bringing an abrupt end to the Conference for Progressive Political Action.

Eugene V. Debs addressed a "mass meeting" including delegates of the convention in a keynote address delivered at the Lexington Hotel early in the afternoon of February 21. After the Debs speech, those delegates favoring establishment of a new political party were then reconvened, with the opponents of an independent political party departing. The reconvened Founding Convention found itself split between adherents of a non-class Progressive Party based upon individual memberships as opposed to the Socialists' conception of a class-conscious Labor Party employing "direct affiliation" of "organizations of workers and farmers and of progressive political and educational groups who fully accept its program and principles." Following extensive debate, the Socialist counter-proposal was defeated by a vote of 93 to 64.[25] The trade unions it coveted gone, the farmers non-existent, the Socialist Party exited the convention and abandoned the strategy of establishing a new mass party through the CPPA. A "Progressive Party" was formed by the remaining liberals, and the group survived for a short time in a limited number of states throughout the 1920s.

Clarence Senior, SPA Executive Secretary from August 1929 to late 1936.

In 1928, the Socialist Party returned as an independent electoral entity under the leadership of Norman Thomas, a radical Protestant minister from New York City. This reentry into the electoral fray behind the dynamic Thomas fueled major growth of the SP during the first years of Great Depression, primarily among youth. A skilled orator and advocate of the step by step solution of social problems, Thomas had excellent access to churches, colleges, and civic institutions. Thomas also had, as New York social democrat Louis Waldman later noted, "those qualities of mind and character which appealed to the intelligent and educated young people of the country and which drew them into the ranks of the party in unprecedented numbers."[26]

The 1928 convention voted to reduce membership dues to just $1 per year, with only half of that sum going to the use of the National Office, the balance being retained by state and local organizations. This level of funding proved insufficient for anything beyond the bare minimum of operations by the National Office in Chicago; no official party publication was made available to the members of the organization, with several privately held socialist newspapers fulfilling the function as fonts of party information.

The dues rate cut did prove helpful in helping to reduce the party's membership slide. After nearly a decade of steady decline, the Socialist Party again began to grow, advancing from a low of under 8,000 dues payers in 1928 to a membership of almost 17,000 by 1932.[27] This growth came at a price however, as deep factional divisions developed between the youthful newcomers (radicalized and drawn to militant Marxism by the world economic crisis) and the "Old Guard" headed by Morris Hillquit, James Oneal, and Waldman.

The generational battle first erupted at the May 1932 Milwaukee Convention. Participant Anna Bercowitz noted four primary factions at this gathering: an "Old Guard" defending the current course of the party and the position of National Chairman Morris Hillquit, practical Socialists of the Milwaukee type, the young Marxist "Militants", and liberal pacifist "Thomasites" such as Devere Allen who followed the lead of the charismatic Thomas:

"The groups which represented the so-called 'New Blood' at the convention, the Militants and the Liberals and which at this convention merged for the sole purpose of deposing the present leadership [of the party] had little in common. Many members of the most aggressive, although numerically weakest of these groups, the Militants, had little in common with the so-called Thomasites.... And as for the so-called Mid-western group, although they cast their vote with the opposition, on fundamentals they too are opposed ot much of the liberalizing tendencies manifest in the party in recent years. Yet they voted, contrary to their usual procedure in their respective communities, with the opposition. That trades had been made there can be no doubt, and that some groups had been used as innocent dupes can also hardly be doubted...

"Fundamentally there is much more in common between the Militants and the so-called 'Old Guard' than between the Militants and the [religious pacifist] Thomasites and surely than between the frank practical 'mid-western' type of Socialists, yet when it was a question of vote on the Russian resolution, on the TU [Trade Union] resolution and on the question of the National Chairman and the Executive Committee votes were not cast on the basis of principles but apparently on the basis of 'trades'. The real difference between the Militants and the 'Old Guard' seems to be based on lack of sufficient activity and on tempo rather than on principle."[28]

Hillquit was challenged at the 1932 convention by Daniel Hoan of Milwaukee, with the Militants and the Thomas group voting for Hoan with the Midwesterners. Hillquit was reelected National Chairman by a vote of 105-86, representing paid memberships of 7526 to 6984. Six members of the newly elected NEC were adherents of the Hillquit-"Old Guard" faction.[29] It is clear that to some large extent the controversy between the young newcomers of the Militant faction and that of the so-called Old Guard can be reduced to this struggle for practical control of the party apparatus. Historian Frank Warren notes that "one cannot understand the Old Guard's actions unless one recognizes its intense desire to maintain its place in the party hierarchy; the drives of the young were a threat to the power of the New York Old Guard." He also adds that "clearly one would falsely idealize the Militants if one failed to recognize that their ambitions were not always selfless."[30]

But in addition to the raw struggle for control of the party apparatus, there was also a divergence of visions about the role of the SP in the then-current crisis of capitalism, with mass unemployment at home and the growth of fascism and militarism abroad. The alternative vision of the Militants would be expressed at the subsequent convention of the party, held in Detroit in June 1934, at which it was Norman Thomas and his tactical allies of the Militant faction which would emerge triumphant. It was this gathering which adopted a new Declaration of Principles which inflamed the "Old Guard" faction on a number of different levels.

Louis Waldman, a top leader of the Old Guard.

The ideological differences between the radical pacifist Thomas and his allies of the Militant faction, on the one hand, and the Old Guard faction, on the other have been succinctly summarized as follows::

"The Old Guard was convinced that the 1934 Declaration of Principles was an open declaration in favor of armed insurrection; Thomas believed it was a necessary statement to indicate that Socialists would not lie down in the face of fascism. The Old Guard believed that the anti-war sections of the Declaration of Principles placed the party under the threat of legal prosecution for advocating unlawful actions to oppose war; again Thomas believed that a strong statement was necessary to put capitalism on warning that if it engaged in imperialist war there would be opposition. The Old Guard believed that a united front with the Communists was immoral and would be disastrous for the Socialists, that even limited united action on specific causes should be banned, and even that exploratory discussions about a united front were going too far. Thomas opposed a united front on a general level, including any joint actions in political contests, but he thought that carefully planned united action on specific cases could, and should, take place. And he believed that it was worth while to conduct exploratory talks, even though he felt they would likely lead to nothing. The Old Guard felt that the Socialists' invitation to unaffiliated radicals and the Party's acceptance of former Communists, Lovestoneites, and Trotskyists was turning the party away from democratic socialism and to Communism. Thomas, though he disagreed with the ideology of these anti-Stalinist Communists, was willing to try to work with a party that included them, if they were willing to accept party discipline and not try to take over the Party. The Old Guard considered the Revolutionary Policy Committee, a far-left group within the Socialist Party, a Communist and anarchist group that had no place in a democratic socialist party. Thomas disagreed with the 'romantic revolutionists' in the Revolutionary Policy Committee (as he disagreed with the 'romantic parliamentarians' of the Old Guard), but still felt it was useful to try to salvage some of the enthusiasm and dedication that went into the Revolutionary Policy Committee by permitting its members to remain in the Party if, again, they followed party policy and party discipline."[31]

In addition to the generational and ideological differences between the young Militant faction and the Old Guard, and their divergence over tempo of activity and party personnel, was great disagreement about matters of symbolism and style. Many of the young radicals dressed and acted in marked contrast to their staid, buttoned-down elders, as New York Old Guard leader Louis Waldman recounted in a 1944 memoir:

"Symptoms of a new and dangerous spirit among the Socialist youth began to become manifest on all sides. The youngsters appeared at meetings of the party in blue shirts and red ties. At first this attracted no special attention, for oddity in dress is no novelty among radicals. But gradually their number increased and we now could see that this was a uniform. The Socialist youth of America, like the fascist youth in Europe, had succumbed to the shirt mania.

"The shirt tendency was followed by the salute mania. In Europe, the Nazi salute was the outstretched arm; here in America the United Front was symbolized by the adoption of the Communist clenched fist salute. This greeting, a raised arm at a slightly different angle from the Nazi or Communist salute, now became routine at all our meetings.... Some of the older members of the party were truly horrified at this totalitarian tendency, but others couldn't resist the trend and fell into line. Among these, I painfully record, was Norman Thomas.

"Along with the blue shirts, the red ties, the clenched fists, the raised arm salute, came the banners, the slogans, the demonstrations; all the trappings that make for totalitarian, unthinking mass fervor. These now became regular features at party gatherings. I can still recall the howl of triumph that rose from these young people at one of our meetings when for the first time Norman Thomas returned the clenched fist salute to them. As I stood at his side, my arms deliberately folded to indicate that I would have no part of this, their cheers for Thomas rose to almost uncontrollable frenzy."[32]

Following its loss on the floor of the Detroit Convention, the Old Guard then took its case to the rank and file of the party, which had been called upon to either approve or defeat the new Declaration of Principles in referendum vote. A "Committee for the Preservation of the Socialist Party" was established and an agitational pamphlet published. New York State Assemblyman Charles Solomon was the author of the group's first polemical piece urging defeat of the 1934 Declaration of Principles by the membership at referendum, entitled Detroit and the Party. In this pamphlet, Solomon decried the Detroit Declaration of Principles as "reckless," observing pointedly that "furious phrases cannot take the place of organized mass power."[33] Solomon noted that over "the past three or four years" there had arisen "certain definite groups" in the ranks of the Socialist Party. He continued:

Haim Kantorovitch, chief theoretician of the Militant faction.

"The Declaration does not stand by itself, in a vacuum, as it were. Important as it is, it does not alone account for the vital struggle that is now being waged in the party. It represents the culminating point of a deep seated antagonism. It is like the straw that breaks or threatens to break the camel's back.

"The Declaration of Principles has brought to the surface divergences which are deep, antagonisms which make of our party not a coherent political organization working harmoniously for a common objective but a battle ground of internecine strife."[34]

Solomon charged that the "so-called 'left'" was "making its position clear" with the Declaration of Principles. "There was no mistaking the flag it had unfurled," he declared, "It was the banner of thinly veiled communism."[35] While he declared that "the Declaration of Principles must be decisively rejected in the referendum," he nevertheless strongly hinted that a factional split was in the offing. Merely defeating the proposed Declaration of Principles was "not enough," he concluded, "The Socialist Party must be made safe for Socialism, for social democracy."[36]

American Socialist Quarterly editor Haim Kantorovitch made the case for the Militant faction in a pamphlet urging approval of the Declaration of Principles at referendum. He observed that

"The declaration of principles does not call for insurrection or violence. It simply states that if capitalism should collapse, the Socialist Party will not shrink from the responsibility of taking power. In case of a collapse of capitalism, if the socialists refuse to take power, the fascists will. To say beforehand that in time of a general collapse of capitalism...the socialists will not dare take power before they have a clear mandate from the majority through a democratic vote, is the same as saying that in case of a general collapse of capitalism the Socialist Party will voluntarily, in the name of democracy, turn over the power to the fascists or other reactionary elements, and continue their democratic propaganda from concentration camps."[37]

The membership of the Socialist Party approved the 1934 Declaration of Principles in its referendum vote, a victory which moved the Old Guard towards the exits — although factional fighting into 1936. The leaders of the Old Guard formed a new rival organization to the Socialist Party, the Social Democratic Federation in 1936 and somewhat reluctantly endorsed Franklin Roosevelt for President in the election of that year. They also worked to establish the American Labor Party (ALP) a labor-oriented umbrella organization that included both socialist and non-socialist elements, putting forward both its own candidates as well as endorsing those of the Democratic and Republican parties.

Norman Thomas, six time Presidential candidate of the Socialist Party.

Norman Thomas and his radical pacifist co-thinkers and their young Marxist allies of the Militant faction sought to build a mass political movement by transforming the Socialist Party into what they called an "all-inclusive party." Not only would an appeal be made to the radical intellectuals and trade unionists who were the historic core of the organization, but an effort would be made to work closely with the Communist Party in joint actions, and to infuse the Socialist Party with the leading personnel of small radical oppositional organizations, including in particular the anti-Stalinist communist groupings headed by Jay Lovestone (the so-called "Lovestoneites") and James P. Cannon (the so-called "Trotskyists"). To be sure, an impressive array of left wing intellectuals came into the Socialist orbit as a result of this venture, including (from the Lovestoneites) Bertram D. Wolfe,[38]Herbert Zam, and Benjamin Gitlow; as well as (from the Trotskyists) Max Shachtman, James Burnham, Martin Abern, and Hal Draper. A broad array of radicals from other tendencies also contributed to the pages of the party's official theoretical journal, including from the Communist Party orbit Joseph P. Lash of the American Student Union, the radical novelist James T. Farrell, public intellectual Sidney Hook, leading American Marxist of the 1910s Louis B. Boudin, and Canadian Trotskyist Maurice Spector, among others.[39]

A very real bid was made to unite the factionalized and marginalized American Left in a common cause — and great hope was held for success in the enterprise. After the rise of the Nazis in Germany and Austria by 1934, no longer did the Communist Party engage in its Third Period epithets against the Socialists as so-called "social fascists". Lillian Symes wrote in the SP's theoretical magazine in February 1937 of the "incredible change" seen to be taking place in the Communist Party in its seeming abandonment of sectarianism and move towards building a broad "people's front" against fascism. At the same time, other radical organizations sought to alter their tactics so as to rapidly build and aggressive left wing organization to stand in opposition to nascent fascism. From early 1934 the French Trotskyist organization had entered the French Socialist Party in an effort to build its strength and win support for its ideas. Pressure to follow this policy of the "French Turn" was building among the American Trotskyist group. For a brief historical moment in 1935 and 1936 the vision of the SP as an "all-inclusive party" which aggregated radical oppositionists and possibly even worked with the Communist Party in common cause seemed achievable.

In January 1936, just as the National Executive Committee of the Socialist Party was expelling the Old Guard, a factional battle was being won in the Trotskyist Workers Party of the United States to join the SP, when a national branch referendum voted unanimously for entry.[40] Negotiations commenced between the Workers Party and Socialist leaderships, with the decision ultimately made to allow admissions only on the basis of individual applications for membership rather than en masse admission of the entire group.[41] On June 6, 1936, the Workers Party's weekly newspaper, The New Militant, published its last issue and announced "Workers Party Calls All Revolutionary Workers to Join Socialist Party."[42] Approximately half of the Workers Party heeded the call and entered the SPA.[43]

Although party leader Jim Cannon later hinted that the entry of the Trotskyists into the Socialist Party had been a contrived tactic aimed at stealing "confused young Left Socialists" for his own organization,[44] it seems that at its inception, the entryist tactic was made in good faith. Historian Constance Myers notes that while "initial prognoses for the union of Trotskyists and Socialists were favorable," it was only later when "constant and protracted contact caused differences to surface."[45] The Trotskyists retained a common orientation with the radicalized SP in their opposition to the European war, their preference for industrial unionism and the CIO over the trade unionism of the American Federation of Labor, a commitment to trade union activism, the defense of the Soviet Union as the first workers' state while at the same time maintaining an antipathy toward the Stalin regime, and in their general aims in the 1936 election.[46]

Norman Thomas attracted nearly 188,000 votes in his 1936 Socialist Party run for President but performed poorly in historic strongholds of the party. Moreover, the party's membership had begun to decline.[47] The organization was deeply factionalized, with the Militant faction split into right ("Altmanite"), center ("Clarity") and left ("Appeal") factions, in addition to the radical pacifists around Norman Thomas and the midwestern "constructive" socialists around Dan Hoan. A special convention was planned for the last week of March 1937 to set the party's future policy, initially intended as an unprecedented "secret" gathering.[48]

Prior to the March convention, the Trotskyist "Socialist Appeal" faction held an organizational gathering of their own, meeting in Chicago, with 93 delegates gathering from February 20–22, 1937.[48] The meeting organized the faction on a permanent basis, electing a National Action Committee of five to "coordinate branch work" and "formulate Appeal policies."[49] Two delegates from the Clarity caucus were in attendance. James Burnham vigorously attacked the Labour and Socialist International, the international organization of left wing parties to which the Socialist Party belonged, and tension rose along these lines among the Trotskyists. United action between the Clarity and Appeal groups was not forthcoming and an emergency meeting of Vincent Dunne and Cannon was held in New York with leaders of the various factions including Thomas, Jack Altman, and Gus Tyler of Clarity. At this meeting Thomas pledged that the upcoming convention would make no effort to terminate the newspapers of the various factions.[50]

No action was taken at the 1937 convention to expel the Trotskyist "Appeal faction," but pressure did continue to build along these lines, fueled by the CPUSA's increasingly hysterical denunciations of Trotsky and his followers as wreckers and agents of international fascism. The convention did pass a ban on future branch resolutions on controversial matters, an effort to rein in the activities of the factions at the local level. It also did ban factional newspapers, a move directly targeting The Socialist Appeal, and formally established The Socialist Call as the party's national organ.

Constance Myers indicates that three factors led to the expulsion of the Trotskyists from the Socialist Party in 1937: the divergence between the official Socialists and the Trotskyist faction on the issues, the determination of Altman's wing of the Militants to oust the Trotskyists, and Trotsky's own decision to move towards a break with the party.[51] Recognizing that the Clarity faction had chosen to stand with the Altmanites and the group around Thomas, Trotsky recommended that the Appeal group focus on disagreements over Spain to provoke a split. At the same time, Thomas, freshly returned from Spain, had come to the conclusion that the Trotskyists had joined the SP not to make it stronger, but to capture the organization for their own purposes.[52] On June 24–25, 1937, a meeting of the Appeal faction's National Action Committee voted to ratcheted up the rhetoric against American Labor Party and Republican nominee for mayor of New York Fiorello LaGuardia, a favorite son of many in Socialist ranks, and to reestablish their newspaper, The Socialist Appeal.[53] This was met with expulsions from the party beginning August 9 with a rump meeting of the Central Committee of Local New York, which expelled 52 New York Trotskyists by a vote of 48 to 2, with 18 abstentions, and ordering 70 more to be brought up on charges.[53] Wholesale expulsions followed, with a major section of the YPSL leaving the party with the Trotskyists.

Secretary of Local New York Jack Altman declared that the Trotskyists "were expelled for attempting to undermine the Socialist Party, for loyalty and allegiance to an opponent organization, the Bureau of the Fourth International, and for refusing to abide by the decisions and discipline of the National convention, the National Executive Committee, and the City Central Committee of the party, and for no other reason."[54] Editor Gus Tyler of The Socialist Call echoed Altman's sentiments, emphasizing that "the Trotskyites have, during the last week ,...abandoned the usual means of inner party controversy — debate and appeals through party channels — and, like the Old Guard, have carried their argument into the public, into the capitalist press."[55] The issuance of a statement by the Trotskyist faction to the New York Times and the relaunch of their own newspaper, The Socialist Appeal, was seen as particularly galling by the Call's' editor.[55]

The youth and militance of the depression-era SP is reflected in the cover of this 1935 song book published by the SP-affiliated Rand School Press.

Things turned out no better with the official Communist Party, devoted as it was to the Stalin regime in the USSR. The February–March 1937 joint plenum of the Central Committee and Central Control Commission of the All-Union Communist Party in the Moscow, which green-lighted a massive avalanche of secret police terror known to history as the Great Purge, changed everything. Baby steps towards multi-candidate elections and the rule of law in the USSR crumbled instantly as show trials, spy mania, mass arrests, and mass executions swept the land. The Trotskyist movement in the USSR was particularly targeted, accused of plotting murder of Soviet officials and conducting sabotage and espionage in preparation for a fascist invasion—seemingly insane charges which were honestly believed by the Soviet elite. Blood flowed like water as alleged Trotskyists and other politically suspect individuals were rounded up, "investigated," and disposed with a pistol shot in the base of the skull or a 10-year sentence in the GULag. Around the world, the adherents of Stalin and Trotsky raged against one another.

In Spain, the country in which the Lovestoneites invested most of their emotional energy as fervid supporters of the Workers' Party of Marxist Unification (POUM), 1937 marked a similar bloodbath, with the Communist Party of Spain achieving hegemony among the Republican forces and conducting bloody purges of their own at the behest of the Soviet secret police. Joint action between Communist oppositionists and the unflinching loyalists to Moscow was henceforth an abject impossibility.

In 1937 Norman Thomas willingly acceded to a request from the League for Industrial Democracy (LID) to author a pamphlet on the topic of "Democracy versus Dictatorship."[56] Thomas pulled no punches about his views of the regime in the USSR:

"There are still in both the eastern and western hemispheres many examples of rather crude and primitive military dictatorships.... The preach a nationalism whose benefits, spiritual or material, to some degree are for all the people. They profess a positive and paternal concern for the masses. If they rule them sternly that is for their own good....

"In the USSR the dictatorship has been the dictatorship of the Communist Party, but all of its professions and all of its performance has been in the name of the entire working class, and the Communist Party still gives lip-service to a final withering away of all dictatorship, even the dictatorship of the proletariat."[57]

Thomas further noted the Communist Party monopoly of press, radio, schools, army, and government and recalled his own recent visit to Moscow, writing:

"The old keenness of political discussion in the party has almost died, at least in so far as policy is concerned. (Criticism of administration is still allowed). A quotation from Stalin is a final answer to all argument. He receives the same sort of exaggerated veneration in public appearances, in the display of his picture, and in written references to him that is accorded to a Mussolini or a Hitler."[58]

Any thought of common-cause with the Communists was now dismissed by Thomas, who indicated that the Communists' fairly recent change of line from fighting the existing trade unions and damning of all political opponents as "social fascists" to attempting to build a "popular front" was merely tactical, related to the perceived needs of Soviet foreign policy in building coalitions with capitalist countries to forestall fascist invasion.[59]

The factional havoc of the move to the "all-inclusive party" paralyzed activity, while the Old Guard's new group, the Social Democratic Federation of America, controlled the bulk of the SP's former property and the allegiance of those best able to fund the organization. The expulsions of the Trotskyists and disintegration of the party's youth section left the organization greatly weakened and gasping for life, its membership level at a new low.

By 1940, only a small committed core remained in the Socialist Party, including a considerable percentage of militant pacifists. The SP continued to oppose Franklin D. Roosevelt's New Deal as a capitalist palliative, arguing for fundamental change through socialist ownership. In 1940 Norman Thomas was the only presidential candidate who failed to support rearmament military support of Great Britain and China. The pacifist Thomas also served as an active spokesman for the isolationist America First Committee during 1941.

After the Japanese bombing of Pearl Harbor in the fall of 1941, and the declaration of war, however, the U.S. defense of itself and war against fascism was supported by most of the remaining Militants and all of the Old Guard. However, the Socialist Party adopted a compromise position that did not openly oppose American participation in the war. Its failure to support the war created a rift with many leaders, like the Reuther Brothers of the United Auto Workers. The pacifist wing of the party did not advocate engaging in any systematic antiwar activities such as the general strike endorsed by the 1934 Declaration of Principles.[60]

But, the Fair Employment Act is generally perceived as a success for African-American labor rights. In 1942, an estimated 18,000 blacks gathered at Madison Square Garden to hear Randolph kick off a campaign against discrimination in the military, in war industries, in government agencies, and in labor unions. Following the act, during the Philadelphia Transit Strike of 1944, the government backed African-American workers' striking to gain positions formerly limited to white employees.

Thomas led his last presidential campaign in 1948, after which he became a critical supporter of the postwar liberal consensus. The party retained some pockets of local success, in cities such as Milwaukee, Bridgeport, Connecticut, and Reading, Pennsylvania. In New York City, they often ran their own candidates on the Liberal Party line.

Reunification with the Social Democratic Federation was long a goal of Norman Thomas and his associates remaining in the Socialist Party. As early as 1938, Thomas had acknowledged that a number of issues had been involved in the split which led to the formation of the rival Social Democratic Federation, including "organizational policy, the effort to make the party inclusive of all socialist elements not bound by communist discipline; a feeling of dissatisfaction with social democratic tactics which had failed in Germany" as well as "the socialist estimate of Russia; and the possibility of cooperation with communists on certain specific matters." Still, he held that "those of us who believe that an inclusive socialist party is desirable, and ought to be possible, hope that the growing friendliness of socialist groups will bring about not only joint action but ultimately a satisfactory reunion on the basis of sufficient agreement for harmonious support of a socialist program."[62]

The Socialist Party and the SDF merged to form the Socialist Party-Social Democratic Federation (SP-SDF) in 1957. A small group of holdouts refused to reunify, establishing a new organization called the Democratic Socialist Federation. When the Soviet Union led an invasion of Hungary in 1956, half of the members of Communist Parties around the world quit; in the U.S., half did, and many joined the Socialist Party.

In 1958 the party admitted to its ranks the members of the recently dissolved Independent Socialist League, which had been led by Max Shachtman. Shachtman had developed a Marxist critique of Soviet Communism as "bureaucratic collectivism", a new form of class society that was more oppressive than any form of capitalism. Shachtman's theory was similar to that of many dissidents and refugees from Communism, such as the theory of the "New Class" proposed by Yugoslavian dissident Milovan Đilas (Djilas).[63] Shachtman was an extraordinary public speaker and formidable in debate, and his intelligent analysis attracted young socialists like Irving Howe and Michael Harrington. Shachtman's denunciations of the Soviet 1956 invasion of Hungary attracted younger activists like Tom Kahn and Rachelle Horowitz.

Shachtman's youthful followers were able to bring new vigor into the Party, and Shachtman encouraged them to take positions of responsibility and leadership. As a young leader, Harrington sent Kahn and Horowitz to help Bayard Rustin with the civil-rights movement. Rustin had helped to spread pacificism and non-violence to leaders of the civil rights movement, like Martin Luther King. Kahn and Horowitz quickly became close assistants of Rustin. The civil rights movement benefited from intelligence and analysis of Shachtman and increasingly of Kahn. Rustin and his young aides, dubbed "The Bayard Rustin Marching and Chowder Society" by Harrington, organized many protest activities. The young socialists helped Rustin and A. Philip Randolph organize the 1963 March on Washington, where Martin Luther King delivered his I Have A Dream speech.

The young socialists' role in the civil rights movement made the Socialist Party more attractive. Harrington, Kahn, and Horowitz were officers and staff-persons of the League for Industrial Democracy (LID), which helped to start the New LeftStudents for a Democratic Society (SDS). The three LID officers clashed with the less experienced activists of SDS, like Tom Hayden, when the latter's Port Huron Statement criticized socialist and liberal opposition to communism and criticized the labor movement while promoting students as agents of social change.[64] LID and SDS split in 1965, when SDS voted to remove from its constitution the "exclusion clause" that prohibited membership by communists:[65] The SDS exclusion clause had barred "advocates of or apologists for" "totalitarianism".[66] The clause's removal effectively invited "disciplined cadre" to attempt to "take over or paralyze" SDS, as had occurred to mass organizations in the thirties.[67]

The experience of the civil rights movement, and the coalition of labor unions and other progressive forces, suggested that America was changing and that a mass movement of the democratic left was possible. In terms of electoral politics, Shachtman, Michael Harrington, and Kahn argued that it was a waste of effort to run electoral campaigns as "Socialist Party" candidates, against Democratic Party candidates. Instead, they advocated a political strategy called "realignment," that prioritized strengthening labor unions and other progressive organizations that were already active in the Democratic Party. Contributing to the day-to-day struggles of the civil-rights movement and labor unions had gained socialists credibility and influence, and had helped to push politicians in the Democratic Party towards social-democratic positions, on civil rights and the War on Poverty.

Bayard Rustin, an important member of the Socialist Party throughout the decade of the 1960s, was elected a National Co-Chairman late in the decade.

In its 1972 Convention, the Socialist Party had two Co-Chairmen, Bayard Rustin and Charles S. Zimmerman (of the International Ladies Garment Workers' Union,[68] ILGWU) and a First National Vice Chairman, James S. Glaser, who were re-elected by acclamation.[69] In his opening speech to the Convention, Co-Chairman Bayard Rustin called for the group to organize against the "reactionary policies of the Nixon Administration"; Rustin also criticized the "irresponsibility and élitism of the 'New Politics' liberals".[69]

The Party changed its name to "Social Democrats, USA" by a vote of 73 to 34.[69] Renaming the Party as SDUSA was meant to be "realistic". The New York Times observed that the Socialist Party had last sponsored a candidate for President in 1956, who received only 2,121 votes, which were cast in only 6 states. Because the Party no longer sponsored candidates in Presidential Elections, the name "Party" had been "misleading"; "Party" had hindered the recruiting of activists who participated in the Democratic Party, according the majority report. The name "Socialist" was replaced by "Social Democrats" because many Americans associated the word "socialism" with Soviet communism.[69] Also, the Party wished to distinguish itself from two small Marxist parties, the Socialist Workers Party and the Socialist Labor Party.[70]

The Unity Caucus had a supermajority of votes and its position carried on every issue, by a ratio of two to one. The Convention elected a national committee of 33 members, with 22 seats for the majority caucus, 8 seats for Harrington's "coalition caucus", 2 for "a Debs caucus", and one for the "independent" Samuel H. Friedman.[71] Friedman and the minority caucuses had opposed the name change.[69]

The convention voted on and adopted proposals for its program by a two-one vote. On foreign policy, the program called for "firmness toward Communist aggression". However, on the Vietnam War, the program opposed "any efforts to bomb Hanoi into submission"; instead, it endorsed negotiating a peace agreement, which should protect Communist political cadres in South Vietnam from further military or police reprisals. Harrington's proposal for an immediate withdrawal of U.S. forces was defeated.[71] Harrington complained that, after its March 1972 convention, the Socialist Party had endorsed George McGovern with a statement loaded with "constructive criticism"; Harrington complained also that the Party had not mobilized enough support for McGovern. The majority caucus's Arch Puddington replied that the California branch had been especially active in supporting McGovern, while the New York branch had instead focused on a congressional race.[70]

Late in October 1972, well before the SP's December convention, Michael Harrington resigned as National Co-Chairman of the Socialist Party.[72] Although little remarked upon at the time despite Harrington's status as "possibly the most widely known of the Socialist leaders since the death of Norman Thomas," it soon became clear that this was the precursor of a decisive split in the organization.[72]

Harrington had written extensively about the progressive potential of the so-called "New Politics" in the Democratic Party and had come to advocate unilateral withdrawal from the Vietnam war and to advocate positions regarded by more conservative party members as "avant-garde" on the questions of abortion and gay rights.[72] This put Harrington and his co-thinkers at odds with the party's younger generation of leaders, who espoused a strongly labor-oriented direction for the party and who were broadly supportive of AFL-CIO leader George Meany.[72]

Passes constitutional amendment requiring support of electoral politics and banning advocacy of sabotage. Again causes NEC and Executive Secretary to be chosen by National Committee, not party referendum. Nominates Debs for 4th time. Stenographic Proceedings Part 1 and Part 2.

Social Democrats, USA (December 1972) [copyright 1973]. The American challenge: A social-democratic program for the seventies. New York: S.D. U.S.A. and YPSL."program ... adopted at the Social Democrats, U.S.A. and Young People's Socialist League conventions at the end of December, 1972." "The S.D. USA" is the "successor to the Socialist Party, USA and the Democratic Socialist Federation of the USA".

Most of the socialist press was privately owned as the party was concerned that a single official publication might lead to censorship in favor of the editors' views, in much the same way Daniel DeLeon used The People to dominate the Socialist Labor Party. A number of papers carried the party's official notices in its first years, the most important being The Worker (New York), The Appeal to Reason (Girard, Kansas), The Socialist (Seattle and Toledo, OH), The Worker's Call (Chicago), St. Louis Labor, and The Social Democratic Herald (Milwaukee).

The party soon discovered that it needed a more regular means of communication with its members and the 1904 National Convention decided to establish a regular party organ. Over the next seven decades, a series of official publications were issued directly by the SPA, most of which are today available on microfilm in essentially full runs:

^Note that the Socialist Party of America was also known at various times in its long history as the "Socialist Party of the United States" (as early as the 1910s) and "Socialist Party USA" (as early as 1935, most common in the 1960s). The original, official name of the organization was "Socialist Party of America," however, and it is so referred to here.

^Hillquit, "What shall the Attitude of the SP Be Toward the Economic Organization of the Workers?" (Haywood Debate) in Hillquit Papers; quoted in Pratt, Morris Hillquit: A Political History of an American Jewish Socialist, p. 106.

^Eugene V. Debs, "The Canton, Ohio Speech, Anti-War Speech", delivered June 16, 1918, first published 1918 in The Call, online at Marxists.org, accessed 11 August 2006.

^Louis Waldman, Albany: The Crisis in Government: The History of the Suspension, Trial and Expulsion from the New York State Legislature in 1920 of the Five Socialist Assemblymen by Their Political Opponents. New York: Boni and Liveright, 1920; pp. 2-7.

^In his history of the 1920 expulsions written just after the fact, Socialist Assemblyman Louis Waldman noted that "expressions of astonishment and indignation flowed in from all parts of the world," including public figures from England, France, Italy, and Argentina. Waldman, Albany: The Crisis in Government, p. 43.

^Charles Solomon, Detroit and the Party. New York: Committee for the Preservation of Socialist Policies, n.d. [1934]; pg. 3. It is worthy of note that the Committee for the Preservation of Socialist Policies was an organized faction to the extent of maintaining an office at 1 Union Square in New York City, complete with a provisional Executive Secretary and National Executive Committee.

^Haim Kantorovich, The Socialist Party at the Crossroads: Notes on the Declaration of Principles Adopted at the National Convention Socialist Party, Detroit, June 3, 1934. New York: Max Delson, July 1934; pg. 15.

^Wolfe co-authored a book with Norman Thomas in 1938, Keep America Out of War.

^The SP's theoretical magazine was known variously as the American Socialist Quarterly (1932–1935), American Socialist Monthly (1935–1937), and Socialist Review (1937–1940). For a short commentary on the publication, see David Herreshoff's article in the section "Publications of the Socialists" in Joseph R. Conlin (ed.), The American Radical Press, 1880-1960. Westport, CT: Greenwood Press, 1974; v. 1, pp. 198-201.

^Myers cites "about 2,000" members for the Workers Party of the US in 1935 (pg. 114) and indicates they entered with "about 1,000" (pg. 140) and exited in 1937 with "1,000 added to their number" (pg. 140). Myers, The Prophet's Army.

^"If we had stood aside, the Stalinists would have gobbled up the Socialist Left Wing and it would have been used as another club against us, as in Spain," he later recalled. James P. Cannon, The History of American Trotskyism. New York: Pioneer Press, 1944; pp. 195-196.

^Norman Thomas, Democracy versus Dictatorship. New York: League for Industrial Democracy, 1937. Thomas wrote in the introduction that "At the request of the LID I have written this pamphlet on one of the great either or's of our time. i do not want it to be though that I think it is the one, all inclusive issue, or even the most vital of the issues before us. That, I think, for reasons which I urged over and over in the last [1936] Presidential campaign, is the issue of socialism versus capitalism. It is not 'democracy versus fascism.' There is not now any such emergency in America as should force socialists into a popular front as a defense for our present imperfect democracy." (pg. 3).

^Although privately owned, The New Leader, published in New York City, was the semi-official organ of the SPA from December 1927 until supplanted by the rival Socialist Call in 1935, a rival New York publication which was also initially privately owned. The New Leader was published by the Rand School, a party organization that left with the party to join the Social Democratic Federation and served as that group's official voice until 1940. After the mid-1940s it was published by the "American Labor Conference on Foreign Affairs" and gradually lost its socialist character.

Kraditor, Aileen S., The Radical Persuasion, 1890-1917: Aspects of the Intellectual History and the Historiography of Three American Radical Organizations. Baton Rouge, LA: Louisiana State University Press, 1981.

Laslett John M., and Lipset, Seymour Martin (eds.), Failure of a Dream? Essays in the History of American Socialism. New York: Doubleday, 1974.